The key to successful development and implementation of thermochemical storage systems is the identification of high energy density and low-cost storage materials. In this work, an industrial waste based on a double salt hydrate, coming from non-metallic mining was studied for thermochemical storage applications. Initially, chemical characterization was performed and determined that carnallite-waste material consists of 73.54 wt% of KCl·MgCl₂·6H₂O and impurities such as NaCl (23.04 wt%), KCl (1.76 wt%) and CaSO₄ (1.66 wt%). Using thermal analyses methods, the operating conditions such as temperatures and partial pressures, were optimized for seasonal thermochemical storage applications to P_Hy = 1.3 kPa and ϑ_Hy = 40 °C, and to P_De = 4.0 kPa and ϑ_De = 110 °C. Under these conditions, the reaction reversibility over 10 cycles (10 years) was significantly high, with only 8.5% decrease in chemical reversibility. Furthermore, the duration of dehydration and hydration isotherms was optimized to 15 and 360 min, respectively. Finally, 1.129 GJ/m³ energy storage density was calculated after the tenth cycle of hydration/dehydration for this material. Hence 7.1 m³ of carnallite was estimated to meet the demand of 8 GJ of energy for an average household during the six months of cold seasons. These results are comparable and competitive with an energy storage density of materials such as K₂CO₃ and MgCl₂, reported as promising for seasonal thermochemical storage applications. It should be noted that carnallite-waste material has no commercial value so far and its use contributes to developing sustainable low-cost thermochemical energy storage systems.

成功开发和实施热化学存储系统的关键是确定高能量密度和低成本的存储材料。在这项工作中，研究了来自非金属采矿的基于双盐水合物的工业废物，用于热化学存储应用。最初，进行了化学表征并确定了角砾石废料由73.54 wt％的KCl·MgCl ₂ ·6H ₂ O和杂质如NaCl（23.04 wt％），KCl（1.76 wt％）和CaSO ₄（1.66 wt％）组成。 ％）。使用热分析方法，针对季节性热化学存储应用将温度和分压等运行条件优化为P _Hy  = 1.3 kPa和ϑ _Hy = 40°C，P _De  = 4.0 kPa，ϑ _De  = 110°C。在这些条件下，经过10个循环（10年）后，反应的可逆性非常高，化学可逆性仅降低了8.5％。此外，脱水和水化等温线的持续时间分别优化为15分钟和360分钟。最后，在该材料的第十次水合/脱水循环之后，计算出1.129 GJ / m ^3的储能密度。因此，估计在寒冷季节的六个月中，平均每个家庭需要7.1 m ³的硬红岩满足8 GJ的能源需求。这些结果与K ₂ CO ₃和MgCl等材料的储能密度相当且具有竞争力₂，据报道对于季节性热化学存储应用很有前途。应该指出的是，迄今为止，硬核石废料没有商业价值，其使用有助于开发可持续的低成本热化学储能系统。